There are already known active substance electrical diffuser devices or appliances, wherein the active substance can be released in different ways, by means of heat, air flow, etc, and the appliance is re-usable.
Other electrical diffuser devices or appliances are also known that are made up of a single container with the active substance in liquid, gel or solid form (tablets, bottles with a wick, etc), where the container may be refilled or else be disposable. The devices composed of a bottle with a wick containing the active ingredient in liquid form are of particular interest, as they have the significant advantages of letting us know the remaining active ingredient capacity at all times and of being able to adjust the rate of release of active ingredient by means of the porosity of the wick. These devices, however, have the drawback of not assuring clean handling since active ingredient in liquid form may leak out in the event of incorrect handling.
Disposable appliances and devices are also known for diffusing active substances or principles, generally based on porous carriers impregnated with active substances, although appliances or devices of this type have the disadvantage of providing no control over the rate of release of the product or its consistency over time.
Finally, there is another type of appliance that consists of a receptacle for liquids with a “breathable” wall, i.e. it lets the vapours pass through but not the liquid, although its use on the market is confined to producing evaporation at room temperature.
In this respect, different documents may be cited each referring to patents, such as PCT 84/02654 or even U.S. Pat. No. 4,161,283, corresponding to volatile product dispenser devices, wherein evaporation takes place at room temperature and wherein membranes impermeable to the liquid but permeable to vapour are used so as to allow the vapour to escape to the exterior but not the liquid.
We may also cite U.S. Pat. Nos. 4,157,787, 3,951,622, 5,716,000 and 5,518,790, all referring to containers with one form and features or the other, but with a permeable membrane that allows the vapour of an active substance contained inside the bottle or container to pass, but always with the common denominator that evaporation takes place at room temperature.
Finally, U.S. Pat. No. 4,849,606 describes a container with a breathable membrane for use as a refill for an electrical diffuser, in this case, evaporation is achieved by means of warming the active ingredient. The drawback of this system is that the whole refill contents are warmed in the same way as if it were a tablet impregnated with active ingredient, so that the active ingredient may eventually be degraded, with the result that the efficiency of the evaporator device is impaired.